How to Make It
Preheat oven to 375°F; line a rimmed baking sheet with foil and mist with cooking spray. Place stuffing mix, dried onion and 1 cup water in a large bowl. Stir and let stand 5 minutes. Add beef, sausage and eggs to bowl; mix until just combined.
Form about 32 2-inch meatballs and place on baking sheet. (It's fine if they touch.) Bake meatballs until cooked through, 35 to 40 minutes, gently shaking pan once or twice.
Bring a large pot of salted water to a boil. Add penne and cook until al dente, about 11 minutes or as package label directs; drain. Warm sauce in pasta pot over medium heat until hot, stirring twice. Turn off heat, return pasta to pot and toss. Serve with meatballs, passing Parmesan at the table.